The present invention relates to an inductively coupled plasma apparatus.
A semiconductor device is manufactured as follows. Firstly, a functional thin film is deposited on a semiconductor wafer by a film forming device. Then, a dry etching device is used to remove unnecessary portions from the thin film to thereby form the functional thin film having a desired pattern. When a plurality of functional thin film layers are deposited on the semiconductor wafer, the plurality of layers are etched in different processing chambers.
An inductively coupled plasma (ICP) etching apparatus is used for the etching processing of semiconductor devises. The ICP etching apparatus has a vacuum vessel made of a dielectric material and an external electrode provided around the outer periphery of the vacuum vessel. A high frequency electric power is supplied to the external electrode, whereby plasma is generated in the vacuum vessel. The thin film is etched by the plasma.
During the processing by the conventional ICP etching apparatus, etching product particles are generated. The etching product particles stick and deposit on an inner wall of the vacuum vessel every time an etching process is carried out. The temperature in the vacuum vessel is significantly different between during the etching processing and during a waiting period. The deposited etching product particles often undergo a temperature difference (heat stress), so that the deposited etching product particles peel off from the wall. Pieces of the peeled etching products drop on the semiconductor wafers. The relatively larger dropped pieces prevent the formation of the semiconductor devices having a desired pattern. In addition, the etching products deposited on the vacuum vessel causes deterioration of an etching rate owing to ignition failure of the plasma and variation of matching points.
The removal of the etching products is performed by daily washing of the vacuum vessel before the processing of articles, dry cleaning sequence scheduled after the processing, and the like. Such a cleaning step shortens an operation life and lowers an operation efficiency of the etching apparatus, which leads to the increase of an operation cost of the etching apparatus and thus a manufacturing cost of the semiconductor devices. Therefore, it has been required to develop inductively coupled plasma apparatuses which can stably and efficiently conduct the processing.
The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an inductively coupled plasma apparatus which can stably conduct continuous processing.
To achieve the above object, the present invention provides an inductively coupled plasma apparatus. The plasma apparatus has a reaction tube made of a dielectric material and having at least curved outer and inner surfaces, a high-frequency antenna arranged around the reaction tube for generating plasma inside the reaction tube, and at least one shield plate arranged in the reaction tube. The shield plate splits a deposition layer composed of reaction product particles to be attached on the reaction tube.
A further perspective of the present invention is a plasma etching apparatus having a cylindrical reaction tube made of a dielectric material, and a high-frequency antenna arranged to face an outer peripheral surface of the reaction tube, for generating plasma inside the reaction tube. The plasma etching apparatus further includes a plurality of shield plates which are arranged to be near an inner peripheral surface of the reaction tube so as to face at least part of the high-frequency antenna and are arranged separate from each other, and a driving device for moving at least one of the high frequency antenna and the reaction tube relative to the other.
Other aspects and advantages of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.